Oceans. I'm fine with them being there, but why do they have to be so absolutely deprived of content? Squids, dirt, sand and water for as far as the eye can see. Every now and then you come across a flooded cave opening, and Strongholds have an annoying tendency to generate under oceans, but apart from that there's nothing fun to do there, and nothing you can't do a hundred times easier on land (apart from fishing and drowning yourself, I guess). It also seems like Mojang has deliberately avoided adding anything to oceans, they haven't had a single new feature since the launch of the game. There could be so much potential, like richer ore deposits generating under oceans (inciting you to make an underwater mining base), sunken treasures, seaweed, coral reefs, deep-sea-excluisive mobs, or loads of other things giving you an incentive to explore the deep blue. As of now, Oceans are just boring, completely resourceless deserts under water.
